(a) Field of the Invention
The present invention relates to a thin film transistor (TFT) array panel for a liquid crystal display (LCD) and a method for manufacturing the same.
(b) Description of the Related Art
Thin film transistors, which are typically used as a switching element in each pixel of an LCD, have an amorphous silicon layer or a polysilicon layer as an active layer.
The polysilicon thin film transistor, because it has a higher carrier mobility compared to the amorphous silicon thin film transistor, may narrow the widths of signal lines for driving the pixels and may be used in a large-scale, high-quality LCD since a driving circuit may be integrated on the substrate of an LCD. Also, because the driving circuit can be formed on the substrate, the overall cost for manufacturing the LCD may be reduced and the overall LCD size may be reduced.
This liquid crystal display using the polysilicon thin film transistor generally includes a first substrate having a plurality of thin film transistors, and a second substrate having a plurality of red, green and blue color filters. Also, a second substrate has a black matrix having an opening that defines a pixel which serves as a light shield for the regions between adjacent pixels where the electric field cannot fully control the liquid crystal layer.
However, the black matrix decreases the aperture ratio of the LCD because it covers a wider area than is necessary for covering the light leakage in order to compensate for misalignment between the two substrates. To avoid this problem, it is suggested that the black matrix be formed on the first substrate. However, this method increases the total number of processes in manufacturing the LCD because an align key must be formed on the second substrate to align the first substrate and the second substrate.